PB2622: A PROSPECTIVE, OPEN-LABEL ONGOING STUDY OF SAFETY AND TREATMENT SATISFACTION IN ADULT IMMUNE THROMBOCYTOPENIA (ITP) SUBJECTS AFTER SWITCHING TO AVATROMBOPAG FROM ELTROMBOPAG OR ROMIPLOSTIM
Authors: Scott Kolodny, Michael Vredenburg, Jessica Zhang, Brian Jamieson
Journal: HemaSphere (2023)

Topic: 32. Platelet disorders Background: Immune Thrombocytopenia (ITP) is an immune-mediated disease resulting in platelet destruction and diminished platelet production. Three TPO-RAs (eltrombopag (ELT), romiplostim (ROMI), and avatrombopag (AVA)) are currently approved in the United States (US) and Europe for the treatment of thrombocytopenia in adult patients with ITP. ROMI is administered via injection, in a health care provider's office in the United States, whereas ELT and AVA are oral medications. Polyvalent cations significantly limit the bioavailability of ELT, therefore patients must follow strict dietary restrictions. AVA is taken with meals and does not carry food-type or timing restrictions, which, along with its route of administration, may be perceived as more convenient for some patients. Observational studies have shown that switching to an alternate TPO-RA may be beneficial if there was an insufficient response to treatment with the initial TPO-RA, which may be due to refractoriness to the previous treatment or non-compliance with the treatment regimen (Kuter DJ, et al. Int J Hematol 2015). A recent retrospective observational study of heavily pre-treated ITP patients at four large tertiary medical centers in the US demonstrated that 91% of AVA patients who switched from ELT and 94% who switched from ROMI achieved a platelet response (platelet count (PC) ≥50,000/uL) regardless of the reason for switch (Al-Samkari H, et al. Br J Haematol 2022). In this study responses were noted in 12/14 (86%) of patients who switched for ineffectiveness of prior TPO-RA, 6/7 (86%) for adverse events experienced on prior TPO-RA, and 23/23 (100%), for convenience reasons. Although the reason for switch was captured in this study, overall treatment satisfaction and patient-reported convenience on therapy were not assessed. With the majority of patients in this real-world analysis switching due to perceived convenience, a study contrasting treatment satisfaction and on-therapy convenience in patients switching to AVA from either ELT or ROMI is warranted. Aims: To assess safety, patient-reported treatment satisfaction and convenience, and PC in adult ITP patients during 90 days of AVA treatment following prior therapy with either ELT or ROMI. Methods: This is a prospective, open-label Phase 4 study conducted in the US (NCT04638829). Approximately 100 subjects will be enrolled, 50 (±10) who have received ELT and 50 (±10) who have received ROMI prior to study entry. The main inclusion criteria: age ≥18 years; subjects have been undergoing treatment for primary ITP with ELT or ROMI for at least 90 days prior to the screening visit; subjects have had a previous response (at any time) to either ELT or ROMI, defined as at least 2 platelet counts ≥50×109/L and informed consent. The main exclusion criteria: any previous AVA use; subjects currently receiving chemotherapy or radiation for any form of cancer.The primary endpoint is occurrence of adverse events and serious adverse events. Key secondary endpoints include: change from baseline in each of the 4 domains of the TSQM Version 1.4 (convenience, global satisfaction, effectiveness, and side effects) to Day 90 or End of Study, with focus on the convenience domain specifically; proportion of subjects who have a platelet count between ≥50×109/L to ≤200×109/L at Day 15, Day 30, Day 60, and Day 90. Results: N/A Summary/Conclusion: This study is currently enrolling at US sites. Data will be shared when available. Keywords: Autoimmune disease, ITP